Downhole sealing tools and method of use

ABSTRACT

A downhole tool apparatus for insertion into and sealing engagement with a wellbore. The apparatus comprises a tube having an expandable diameter, and a gripping member joined to the tube adapted to engage a portion of the wellbore to limit movement of the tube within the wellbore. The tube may also include a sealing member adapted to mate with the wellbore to form a sealing engagement.

BACKGROUND

[0001] The present invention relates generally to downhole sealingsystems for use in subterranean wells.

[0002] In the drilling and completion of oil and gas wells, a greatvariety of downhole tools are used. For example, but not by way oflimitation, it is often desirable to seal tubing or other pipe in thecasing of the well. Downhole tools referred to as packers and bridgeplugs are designed for these general purposes and are well known in theart of producing oil and gas.

[0003] When it is desired to remove many of these downhole tools from awellbore, it is frequently simpler and less expensive to mill or drillthem out rather than to implement a complex retrieving operation. Inmilling, a milling cutter is used to grind the packer or plug, forexample, or at least the outer components thereof, out of the wellbore.Milling is a relatively slow process, but milling with conventionaltubular strings can be used to remove packers or bridge plugs havingrelative hard components such as erosion-resistant hard steel.

[0004] In drilling, a drill bit is used to cut and grind up thecomponents of the downhole tool to remove it from the wellbore. This isa much faster operation than milling, but requires the tool to be madeout of materials which can be accommodated by the drill bit.

[0005] Such drillable devices have worked well and provide improvedoperating performances at relatively high temperatures and pressures. Anumber of U.S. patents in this area have been issued to the assignee ofthe present invention, including U.S. Pat. Nos. 5,224,540; 5,271,468;5,390,737; 5,540,279; 5,701,959; 5,839,515; and 6,220,349, which arehereby incorporated by reference herein in their entirety. However,drilling out hardened iron components may require certain techniques toovercome known problems and difficulties. The implementation of suchtechniques often results in increased time and costs.

[0006] Improvements in the area of drillable downhole tools are stillneeded and the present invention is directed to that need.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1A is a partial cross-sectional view of a wellbore casinghaving a downhole tool disposed therein according to a first embodimentof the present invention.

[0008]FIG. 1B is a partial cross-sectional view of the downhole tool ofFIG. 1A shown in a sealing configuration.

[0009]FIG. 1C is a detailed partial cross-sectional view of a grippingelement which may be used by the embodiments of the present invention.

[0010]FIG. 1D is a detailed partial cross-sectional view of a grippingelement which may be used by the embodiments of the present invention.

[0011]FIG. 1E is a detailed partial cross-sectional view of a grippingelement which may be used by the embodiments of the present invention.

[0012]FIG. 1F is a detailed partial cross-sectional view of a sealingmember which may be used by the embodiments of the present invention.

[0013]FIG. 1G is a detailed partial cross-sectional view of a sealingmember which may be used by the embodiments of the present invention.

[0014]FIG. 1H is a detailed partial cross-sectional view of the sealingmember of FIG. 1G shown in a sealing configuration.

[0015]FIG. 2 is a partial cross-sectional view of a wellbore casinghaving a downhole tool disposed therein according to a second embodimentof the present invention.

[0016]FIG. 3A is a partial cross-sectional view of a wellbore casinghaving a downhole tool disposed therein according to a third embodimentof the present invention.

[0017]FIG. 3B is a partial cross-sectional view of the downhole tool ofFIG. 3A shown in a first sealing configuration.

[0018]FIG. 3C is a partial cross-sectional view of the downhole tool ofFIG. 3A shown in a second sealing configuration.

[0019]FIG. 4A is a partial cross-sectional view of a wellbore casinghaving a downhole tool disposed therein according to a fourth embodimentof the present invention.

[0020]FIG. 4B is a partial cross-sectional view of the downhole tool ofFIG. 4A shown in a sealing configuration.

[0021]FIG. 5A is a partial cross-sectional view of a wellbore casinghaving a downhole tool disposed therein according to a fifth embodimentof the present invention.

[0022]FIG. 5B is a partial cross-sectional view of the downhole tool ofFIG. 5A shown in a sealing configuration.

[0023]FIG. 6A is a partial cross-sectional view of a wellbore casinghaving a downhole tool disposed therein according to a sixth embodimentof the present invention.

[0024]FIG. 6B is a partial cross-sectional view of the downhole tool ofFIG. 6A shown in a sealing configuration.

DETAILED DESCRIPTION

[0025] Referring to FIG. 1A, there is shown disposed in a well a wellcasing 10 having an internal surface 12 with an internal diameter. Itwill be understood that the well casing 10 may represent any tubularmember disposed within a subterranean wellbore including tubing, jointedpipe, coiled tubing, or any other tubular structure that may bepositioned in a subterranean wellbore. Disposed within the well casing10 is a workstring 14 having external threads 15 at its lower end and aninternal fluid passage 16. A downhole tool 20 is suspended on theworkstring 14 by engagement of the external threads 15 with internalthreads 17 disposed in an upper plug 18 of the downhole tool 20. Inalternative embodiments, the downhole tool 20 could also be suspended ona wire line, coiled tubing, or attached to the workstring 14 with astandard adapter kit, known in the art. The well can be either a casedcompletion as shown in FIG. 1A or an openhole completion.

[0026] The downhole tool 20 is comprised of a tubular member 22 havingan outer surface 24 and an inner surface 26. In one aspect of theinvention, the tubular member 22 is formed of a substantially uniformmaterial throughout and may include a single material or be a compositeof several different materials distributed throughout the tubular member22. The tubular member 22 may be made from a relatively expandablematerial so that it can expand horizontally as explained in more detailbelow. These materials are preferably selected such that the packingapparatus can withstand wellbore working conditions with pressures up toapproximately 10,000 psi and temperatures up to about 425° F. In onepreferred embodiment, but without limitation, the materials of thedownhole tool 20 are selected such that the downhole tool 20 canwithstand well pressures up to about 5,000 psi and temperatures up toabout 250° F. Such materials may include engineering grade plastics andnylon, rubber, phenolic materials, or composite materials. As will beexplained in greater detail in reference to FIGS. 1C through 1H, theouter surface 24 includes a plurality of grips 28 and sealing members30. It is anticipated that the grips 28 will have a hardnesssubstantially greater than the material forming the tubular member 22and that sealing members 30 will have a hardness less than the hardnessof the material forming the tubular member 22.

[0027] The downhole tool 20 separates the well casing 10 into an uppercasing passage 32 and a lower casing passage 34. The inner surface 26 ofthe tubular member 22 defines an internal chamber 38 enclosed by theupper plug 18 engaging the upper end of the downhole tool 20 and a lowerplug 42 engaging the inner surface 26 adjacent to the lower end of thedownhole tool 20. The upper plug 18 includes a one-way valve 48configured to permit flow into the internal chamber 38 from the fluidpassage 16 in the workstring 14 and to limit flow out of the internalchamber 38 back into the fluid passage 16. The one-way valve 48comprises a ball 52, a valve seat 54, and a ball stop 56. When the ball52 is positioned adjacent to the ball stop 56 and spaced from the valveseat 54, fluid may flow around the ball 52 into the internal chamber 38.However, when the ball 52 engages the valve seat 54, fluid flow frominternal chamber 38 into the fluid passage 16 is prevented.

[0028] The lower plug 42 may also include a one-way valve 58. Theone-way valve 58 is identical to, and operates in a manner similar to,the one-way valve 48. The one-way valve 58 may be adapted to permitfluid flow into the internal chamber 38 and limit fluid flow out of theinternal chamber 38 into the lower casing passage 34, as will bedescribed below.

[0029] In FIG. 1A, the downhole tool 20 is illustrated in a “run in” orinsertion configuration with the tubular member 22 having a maximumdiameter D1 and a length L1. FIG. 1B depicts the downhole tool 20 afterit has been expanded in a manner to be described, to a set configurationin which it has a diameter D2 and a length L2. It will be understoodthat the diameter D2 is greater than the diameter D1 such that grips 28are urged against the internal surface 12 to maintain the longitudinalposition of the downhole tool 20. In a preferred aspect, the grips 28 atleast slightly penetrate the internal surface 12 to thereby resistlongitudinal movement of the downhole tool 20. In a similar manner, theexpansion of the downhole tool 20 to the diameter D2 urges the sealingmembers 30 against the internal surface 12 to establish a fluid sealagainst the well casing 10. In the illustrated embodiment, the expansionof the diameter from D1 to D2 also results in shortening of the lengthfrom L1 to L2. Furthermore, as shown in FIG. 1A, the tubular member 22has an initial wall thickness T1 and a wall thickness T2 (FIG. 1B) inits expanded configuration. In the illustrated embodiment, the wallthickness T1 and the wall thickness T2 are substantially equal such thatthe expansion of the tubular member 22 has little impact on its wallthickness. It will be appreciated by those skilled in the art that thetubular member 22 may be constructed such that the relationship betweenthe wall thickness, length, and diameter of the downhole tool 20 areengineered to establish the desired tradeoffs during the expansionprocess. More specifically, it will be understood that in an alternativeembodiment the length L1 and L2 may be substantially identical with theexpansion in diameter resulting primarily from a change in the wallthickness T1 to the smaller wall thickness T2.

[0030] In operation, the downhole tool 20 may be interconnected with theworkstring 14 via the engagement of the external threads 15 with theinternal threads 17. In alternative methods, the downhole tool 20 couldbe positioned with a wire line, coiled tubing or other known wellservice tools. The downhole tool 20 is initially in the insertion orrun-in configuration shown in FIG. 1A and, as such, is advanced throughthe well casing 10 to the desired tool location. When it is desired toshift the downhole tool 20 from its insertion configuration to itssealing or set configuration, fluid pressure in the fluid passage 16 ofthe workstring 14 is transmitted into the internal chamber 38 throughthe one-way valve 48. The initial pressure in the internal chamber 38causes the one-way valve 58 to close, thereby permitting an increase inthe pressure in the internal chamber 38. The increasing pressuredifferential between the internal chamber 38 and the upper and lowercasing passages 32 and 34 causes the tubular member 22 to expand to thediameter D2. Once the downhole tool 20 has been expanded in the wellcasing 10, the fluid pressure in the fluid passage 16 may be decreasedwith respect to the internal chamber 38, which will close the one-wayvalve 48. The workstring 14 may then be disengaged leaving the downholetool 20 in position to seal and engage the well casing 10. Suchdisengagement may be accomplished by known methods such as by shearingthe interconnection between the workstring 14 and the downhole tool 20.

[0031] It is contemplated that the materials of the tubular member 22will undergo at least partial elastic deformation during the expansionprocess. With such material selection, the tubular member 22 will tendto contract upon removal of pressure from the internal chamber 38.Alternatively, the material selected for the tubular member 22 mayundergo a plastic deformation during the expansion process to maintaingrips 28 in engagement with the well casing 10 during the drill outprocedure.

[0032] In still a further alternative, the internal chamber 38 could bepreliminarily pressurized by fluid pressure in the fluid passage 16 ofthe workstring 14 acting through one-way valve 48 as described above.The preliminary pressurization would at least partially urge the sealingmembers 30 and the grips 28 against the internal surface 12. After thepreliminary pressurization, pressure inside the fluid passage 16 and thewell casing 10 above the downhole tool 20 would be reduced creating apressure differential across the downhole tool 20. The higher pressurefluid from below the downhole tool 20 will enter the internal chamber 38through the one-way valve 58 and will forcefully urge the tubular member22 outwardly against the internal surface 12. In this situation, theone-way valve 48 would close allowing the pressure in the internalchamber 38 to increase until it corresponds to the pressure in the wellcasing 10 below the downhole tool 20. Workstring 14 may be disengagedfrom the downhole tool 20 after complete seating of the downhole tool 20in the wellbore.

[0033] Once the internal chamber 38 is pressurized by either of theforegoing techniques, the downhole tool 20 is left in place to provide aseal between the upper casing passage 32 and the lower casing passage34. The downhole tool 20 remains in place while other well operations,known in the art, are performed. Upon the completion of such welloperations, the downhole tool 20 may be removed from the wellbore by topdrilling the device or by any other known oil field techniques. Duringthe removal procedure, a drill member (not shown) may engage the one-wayvalve 48 and forcibly unseat the ball 52 from the valve seat 54. It willbe understood that this operation will, over time, equalize the pressurebetween internal chamber 38 and the upper casing passage 32.Furthermore, the one-way valve 58 would then be free to open such thatpressure below the downhole tool 20 may also be equalized.

[0034] Once the pressure has been equalized, the drill may then continueto remove the non-metallic materials forming the sealing device. Instill a further alternative aspect, tubular member 22 may be designed torelax to a smaller diameter configuration upon pressure release. In thisembodiment, the downhole tool 20 may be moved within the well casing 10after pressure release using hydraulic or mechanical forces.

[0035] In another embodiment, the tubular member 22 has a naturaltendency to expand greater than the diameter of the internal surface 12,thereby continuing to urge grips 28 into contact with the well casing 10in the absence of a pressure differential. In this embodiment, thetubular member 22 is mechanically held in the elongated configurationshown in FIG. 1A, for example, by an inner mandrel (not shown) extendingbetween the upper plug 18 and the lower plug 42. As the mechanicalelongation force is withdrawn, the tubular member 22 may relax to theposition shown in FIG. 1B.

[0036] A variety of grip and seal embodiments may be used with thevarious aspects of the present invention. By way of illustration, someof these embodiments are illustrated in FIGS. 1C through 1H. Referringnow to FIG. 1C, there is shown a portion of the tubular member 22.Embedded in an exterior surface 72 is a grip member 74 disposed within arecess 75 to maintain its relative longitudinal position along thetubular member 22. The grip member 74 may be molded with the exteriorsurface 72 such that it is firmly embedded in the material of thetubular member 22. Alternatively, the grip member 74 may be bonded tothe exterior surface 72 using adhesives or cement. Still further, it iscontemplated that the grip member 74 may be mechanically coupled to theexterior surface 72. The grip member 74 has a point or a substantiallyhorizontal edge 76. The grip member 74 is made from a relatively hardermaterial than the tubular member 22 so that the point or edge 76 canengage the internal surface 12 of the well casing 10 (FIG. 1A).

[0037] The grip member 74 may be made of either metallic or non-metallicmaterial. If made from non-metallic material, then the materials couldinclude engineering grade nylon, phenolic materials, epoxy resins, andcomposites. The phenolic materials may further include any of FIBERITEFM4056J, FIBERITE FM4005, or RESINOID 1360. These components may bemolded, machined, or formed by any known method. One preferred plasticmaterial for at least some of these components is a glass reinforcedphenolic resin having a tensile strength of about 18,000 psi and acompressive strength of about 40,000 psi, although the invention is notintended to be limited to this particular material or a material havingthese specific physical properties.

[0038]FIG. 1D illustrates another embodiment of a grip member. In thisembodiment, a wedge 80 is formed with the tubular member 22. The wedge80 may be made from a material, such as metal, having a hardnesssufficient to grippingly engage the internal surface 12 of the wellcasing 10, although penetrating engagement is not required to maintainthe position within the well casing 10. The wedge 80 may be a horizontalsemi-circular shape positioned at various points around thecircumference of the downhole tool 20. Using a series of short wedges,as opposed to a single radial wedge, would allow the downhole tool 20 toexpand without developing ring tension in the wedge 80.

[0039]FIG. 1E illustrates another embodiment of a grip member withsealing capabilities. This embodiment is similar to the embodimentdiscussed with reference to FIG. 1D. However, in this embodiment, anexterior surface 90 is coated with a sealing layer 92. The sealing layer92 may be engineering grade plastic, rubber, phenolics, or composites.Preferably sealing layer 92 is formed of a softer material than thetubular member 22 such that wedge 80 may be forced through the materialto engage the well casing 10. The sealing layer 92 provides a seal whenthe wedge 80 is engaged into the internal surface 12 of the well casing10.

[0040]FIG. 1F depicts an embodiment of a sealing member. A sealingmember 94 is embedded into a recess 96 in the tubular member 22. In thisembodiment, the sealing member 94 is rectangular in cross-sectionalshape. However, any appropriate cross-sectional shape may be used. Forinstance, the sealing member 94 could also have a triangular or circularcross sectional shape, or any combination of shapes. As previouslyexplained, the tubular member 22 may be made from a flexible engineeringgrade plastic, rubber, phenolics, or composites so that it can expandhorizontally. The sealing member 94 may be made from engineering gradeplastics, rubber, phenolics, or composite that have greater elasticitythan the tubular member 22 so that the sealing member 94 will presstightly up against the internal surface 12, thereby creating aneffective vertical seal.

[0041] A detail of a grip and seal combination system is shown in FIG.1G. A grip and seal combination 100 includes a plurality of grippingprojections 102 a, 102 b, and 102 c extending from the outer surface ofthe tubular member 22. The gripping projections 102 a, 102 b, and 102 care formed of a substantially hardened material. Sealing members 104 aand 104 b formed of a substantially softer material than the grippingprojections 102 a, 102 b, and 102 c, such as engineering grade materialsdescribed above, are shown disposed between the gripping projections 102a, 102 b, and 102 c. It will be understood that as the tubular member 22expands, the sealing members 104 a and 104 b are compressed against theinternal surface 12 of the well casing 10. As illustrated in FIG. 1H,this compression causes the sealing members 104 a and 104 b to yieldsuch that the harder tips of the gripping projections 102 a, 102 b, and102 c can project beyond the sealing members 104 a and 104 b forengagement with the well casing 10.

[0042] Referring now to FIG. 2, there is shown another embodiment of thepresent invention. A sealing device or downhole tool 110 is shown inFIG. 2 in an insertion configuration positioned within a wellenvironment as previously described including the well casing 10,internal surface 12, workstring 14, fluid passage 16, upper casingpassage 32 and lower casing passage 34. The sealing device 110 includesa tubular member 112 having an outer surface 114 and an internal chamber116. In the illustrated embodiment, an expandable ring member 118 a isdisposed about an upper portion of the tubular member 112. Similarly, alower expandable ring member 118 b is disposed about a lower portion ofthe tubular member 112. The inner surfaces 120 a and 120 b of the ringmembers 118 a and 118 b are in hydraulic communication with the internalchamber 116 through a plurality of openings 124 a and 124 b,respectively, which are spaced radially around the tubular member 112.Although two ring members 118 a and 118 b are illustrated in FIG. 2, anynumber of ring members could be employed vertically along the tubularmember 112.

[0043] A plurality of grips 126 a and 126 b are disposed on the ringmembers 118 a and 118 b, respectively. Similarly a plurality of sealingmembers (not shown) such as the sealing members 94 and 104 of previousembodiments may also be disposed on one or both of the ring members 118a and 118 b. Also, the grips 126 could include the sealing layer 92discussed above in reference to FIG. 1E.

[0044] The internal chamber 116 is bounded by an upper plug 128 and alower plug 130. The upper plug 128 includes a one-way valve 132permitting fluid flow into the internal chamber 116 but inhibiting fluidleaving the internal chamber 116. In a similar fashion, the lower plug130 includes a one-way valve 134 permitting fluid flow into the internalchamber 116 but preventing fluid flow therefrom.

[0045] In operation, the downhole tool 110 is interconnected with theworkstring 14 as discussed above with reference to FIG. 1A. The downholetool 110 is initially in the insertion or run-in configuration as shownin FIG. 2. The workstring 14 is advanced through well casing 10 to thedesired tool location. Then the downhole tool 110 is deployed into itssealing configuration to force the plurality of grips 126 a and 126 bagainst the internal surface 12 of the well casing 10. Morespecifically, fluid pressure developed through the fluid passage 16 ofthe workstring 14 is transmitted through the one-way valve 132 into theinternal chamber 116. Fluid pressure may be applied through the openings124 a and 124 b to the inner surfaces 120 a and 120 b. The pressureexerted on the inner surfaces 120 a and 120 b causes the ring members118 a and 118 b to expand until the grips 126 a and 126 b reach theinternal surface 12 of the well casing 10. Depending on theconfiguration, this expansion forces the grips 126 a and 126 b, alsoknown as sealing members, against the internal surface 12 of the wellcasing 10. In one aspect as shown in FIG. 2, the grips 126 a and 126 bare configured for at least partial penetrating engagement with theinternal surface 12 of the well casing 10.

[0046] In a manner similar to that discussed above in reference toFIG.1, the internal chamber 116 could also be pressurized by pressureentering the internal chamber 116 through the one-way valve 134. In anyevent, once the internal chamber 116 is pressurized and the well casing10 is engaged by the grips 126 a and 126 b, the workstring 14 may thenbe disengaged leaving the downhole tool 110 in position to seal andengage the well casing 10. Thus, the downhole tool 110 is left in placeto provide a seal between the upper casing passage 32 and the lowercasing passage 34. The downhole tool 110 remains in place while otherwell operations, known in the art, are performed. Upon the completion ofthe well operations, the downhole tool 110 may be removed from the wellcasing 10 by top drilling the device or by other such removal methods.

[0047] Referring now to FIG. 3A, there is illustrated another embodimentof the present invention disposed within the well casing 10 having aninternal surface 12. The downhole tool 150 includes an upper tubularmember 152 and a lower tubular member 154. In a preferred aspect, alayer 153 formed of a harder material is disposed between the upper andlower tubular members 152 and 154. The upper and lower tubular members152 and 154 and the layer 153 may be joined together via bonding orother similar material. Further, while independent tubular members areshown, it is contemplated that the upper tubular member 152 and thelower tubular member 154 may be integrally formed with one another withthe exclusion of intermediate layer 153.

[0048] The upper tubular member 152 includes an outer surface 156 and anopposing inner surface 158. The inner surface 158 may include threadsadapted for engagement with a tool string, coiled tubing, wire line, orother well tool. The downhole tool 150 includes an upper flange 157 anda lower flange 159, each having a maximum outer diameter closelyapproximating the internal diameter of the well casing 10. The outersurface 156 includes a plurality of grips 160 and a sealing member 162.In an alternative embodiment, the grips 160 and the sealing member 162may be joined to the outer surface 156 as previously described withrespect to the embodiments discussed in reference to FIGS. 1A throughFIG. 1H. The inner surface 158 defines an internal chamber 164 which isfurther bounded by a tapered surface 166 and a bottom surface 168. Theinternal chamber 164, tapered surface 166, and bottom surface 168 can besaid to define both an open end and a closed end of the upper tubularmember 152. An annulus 173 is formed between the internal surface 12 andthe outer surface 156. In the illustrative embodiment, a one-way valve170 including a ball member 174 is disposed in the tapered surface 166and permits fluid flow from the annulus 173 into the internal chamber164 through a port 171. Fluid flow in the opposite direction isprevented by the ball member 174. The lower tubular member 154 isconstructed in substantially the same configuration as the upper tubularmember 152 and defines an internal chamber 176 including a one-way valve178 communicating through a port 180 to the annulus 173.

[0049] The downhole tool 150 may be interconnected with the tool string14 of FIG. 1A and advanced to the desired location in the well casing10. To expand the downhole tool 150 to an expanded configuration,hydraulic pressure is applied in the internal chamber 164 to establish apressure differential between the internal chamber 164 and the annulus173. In a preferred aspect, the upper flange 157 and the lower flange159 tend to limit fluid flow past the downhole tool 150 through theannulus 173 thereby assisting in establishing a pressure differentialacross the tool. The one-way valve 170 is forced to a closed positionsuch that fluid flow between the internal chamber 164 and the port 171is prohibited. Hydraulic pressure in the internal chamber 164 urges thediameter of the upper tubular member 152 to increase such that the grips160 and the sealing member 162 are in engagement with the internalsurface 12 as shown if FIG. 3B. However, the lower tubular member 154remains substantially in the insertion configuration.

[0050] Alternatively, the downhole tool 150 could be expanded by usingthe wellbore pressure applied to the internal chamber 176. FIG. 3Cillustrates this situation, where the lower tubular member 154 has beenexpanded to a sealing configuration such that a sealing member 182 and aplurality of grips 184 (similar to the sealing member 162 and the grips160 previously described) are in engagement with the internal surface12. Furthermore, the one-way valve 178 is in a closed position toprevent fluid flow from downhole tool 150 to pass beyond the lowertubular member 154 into the annulus 173.

[0051] Once either the internal chamber 164 or 176 has been pressurizedand the well casing 10 is engaged by the grips 160 or 184, theworkstring 14 may then be disengaged leaving the downhole tool 150 inposition to seal and engage the well casing 10. The downhole tool 150remains in place while other well operations, known in the art, areperformed. Upon the completion of the well operations, the downhole tool150 may be removed from the wellbore by top drilling the device or othersuch removal methods.

[0052] Referring now to FIGS. 4A and 4B, there is shown a furtherembodiment of a downhole tool 200 according to an alternative aspect ofthe invention. As previously depicted, the environment includes the wellcasing 10, internal surface 12, upper casing passage 32 and lower casingpassage 34. In this embodiment, the downhole tool 200 includes a tubularbody or cup 202 having a plurality of grips 204 disposed on an outersurface 203 along with a circumferential sealing member 206. The cup 202has an internal surface 207 extending at a slight taper from an upperportion or end to a lower portion or end and defining an internalchamber 208. Furthermore, the tapered internal surface 207 includes aplurality of projections or ridges 209. An expansion plug 216 includesan outer surface 218 have a taper approximating the configuration of theinternal surface 207 and a plurality of ridges or projections 220adapted to interdigitate with the ridges 209. The plug 216 also includesa plurality of fluid passages 222 and a central passage.

[0053] A mandrel 210 extends from the lower portion of the cup 202through the internal chamber 208 and above the cup 202. The mandrel 210is fixedly engaged to the cup 202 by an enlarged flange 212 and mayinclude an internal passage 213 for the movement of fluids between theupper casing passage 32 and the lower casing passage 34. A one-way valve214 including a ball 215 may be disposed in mandrel 210 to initiallyblock fluid flow. The mandrel 210 extends through the central passageformed in the plug 216. The plug 216 is disposed about the mandrel 210and is adapted for longitudinal movement along the mandrel 210.

[0054] In operation, the cup 202 and the plug 216 are coupled on mandrel210 as shown in FIG. 4A. The downhole tool 200 is then run in to thedesired location within the well casing 10 via a tool string such aspreviously described. The cup 202 is then held in position within thewell casing 10 by upward force on the mandrel 210 via the tool string.The plug 216 is then advanced into the internal chamber 208 by a tubularmember (not shown) acting on the top of the plug 216 to force it intothe cup 202. The movement of the plug 216 into the internal chamber 208expands the diameter of the cup 202 to forcibly engage the sealingmember 206 and the grips 204 with the internal surface 12 of the wellcasing 10 as is illustrated in FIG. 4B. Fluid trapped in the internalchamber 208 may escape through the fluid passageways 222. The engagementof the ridges 209 with the ridges 220 maintains the plug 216 within theinternal chamber 208.

[0055] Once the cup 202 has expanded, the downhole tool 200 may be leftin place to provide a seal between the upper casing passage 32 and thelower casing passage 34. The downhole tool 200 remains in place whileother well operations, known in the art, are performed. Upon thecompletion of the well operations, the downhole tool 200 may be removedfrom the wellbore by conventional methods. Upon removal, the one-wayvalve 214 may be initially removed to establish a fluid path from belowthe downhole tool 200 to above the downhole tool 200 to thereby equalizepressure across the downhole tool 200. A drill or milling apparatus maythen be advanced to quickly remove the relatively soft materials of thedownhole tool 200 to thereby re-establish fluid flow between the upperand lower casing passages 32 and 34 of the well casing 10.

[0056] Still a further embodiment according to the present invention isshown in FIGS. 5A and 5B within the well environment previouslydescribed including the well casing 10 and the internal surface 12. Asealing apparatus or downhole tool 250 comprises a flexible ball 252disposed between a plurality of upper legs or gripping elements 254 anda plurality of lower legs or gripping elements 256 spaced about acentral mandrel 262. Each of the upper gripping elements 254 includesgripping teeth 258 on one end and is connected to an upper grippinghousing 255 on the opposite end. In a similar manner, each of the lowergripping elements 256 includes gripping teeth 260 at one end and isconnected to a lower gripping housing 257 on the opposite end. The ball252 includes a central aperture extending from an upper portion to alower portion. The mandrel 262 extends through the central aperture, thecenter of the upper gripping housing 255, and the lower gripping housing257. The mandrel 262 includes a central fluid passage 268 and aroughened outer surface consisting of a plurality of projections orteeth 270. It is understood that the mandrel 262 may include a valve(not shown) disposed in the fluid passage 268 to permit equalization ofpressure above and below the sealing apparatus 250.

[0057] A ratchet assembly 272 is configured to ride on the mandrel 262such that it may be advanced downhole and engage the teeth 270 toprevent upward movement of the upper gripping housing 255 along themandrel 262. The ball 252 may be formed of an integral material,composite materials, or may comprise an external shell that has a fluiddisposed in an interior chamber. In the relaxed condition shown in FIG.5A, the ball 252 is substantially spherical and in the deformedcondition depicted in FIG. 5B, the ball 252 is substantially toroidal.

[0058] In operation, the sealing apparatus 250 may be interconnectedwith a workstring (not shown) and lowered into the well casing 10 to thedesired location. The workstring may include an inner mandrel and anouter sleeve longitudinally moveable along the inner mandrel. The innermandrel may be coupled to the mandrel 262 and the outer sleeve may bepositioned adjacent the ratchet assembly 272. The sealing apparatus 250may be set into a sealing configuration by utilizing mechanical forceapplied by the inner mandrel to hold the mandrel 262 stable as the outersleeve acts against the ratchet assembly 272 to push it down the mandrel262 toward lower gripping housing 257. The upper gripping housing 255and the attached gripping elements 254 move longitudinally downhole withrespect to the mandrel 262 to thereby urge the gripping teeth 258 intoengagement with the internal surface 12 of the well casing 10. Furthermovement of the ratchet assembly 272 downhole towards the lower grippinghousing 257 tends to compress the ball 252 to a deformed shape which inturn applies force against the lower gripping elements 256 therebyforcing the gripping teeth 260 into engagement with the internal surface12. The engagement of the gripping teeth 258 and 260 with the internalsurface 12 inhibits movement of the sealing apparatus 250 within thewell casing 10. Additionally, deformation of the ball 252 forces theouter surface of the ball 252 against the internal surface 12 of thewell casing 10 and continues to deform the ball 252 to provide asubstantial area of deformation creating a substantial area of sealingcontact with the internal surface 12. The ratchet assembly 272 fixedlyengages the teeth 270 on the mandrel 262 to fix the relativelongitudinal position of the gripping housings 255 and 257, thusmaintaining the sealing apparatus 250 in the illustrated sealingconfiguration depicted in FIG. 5B.

[0059] Once the sealing apparatus 250 has been set in a sealingconfiguration, the sealing apparatus 250 may be left in place to providea seal between the upper casing passage 32 and the lower casing passage34 while other well operations, known in the art, are performed. Uponthe completion of the well operations, the sealing apparatus 250 may beremoved from the well casing 10 by top drilling the device. During theremoval procedure, a drill member (not shown) may disengage an upperone-way valve (not shown), which will, over time, equalize the pressurebetween upper casing passage 32 and the lower casing passage 34.

[0060] Referring now to FIGS. 6A and 6B, there is shown a furthersealing system or downhole tool 280 according to another aspect of thepresent invention disposed in a well casing 10 with an internal surface12. The sealing system 280 includes a circular upper form 282 and acircular lower form 284 spaced from one another to form a cavity 283. Amandrel 286 extends through a centrally located aperture 285 in theupper form 282 and a smaller aperture in the lower form 284 to associatethe upper and lower forms 282 and 284 as a sealing unit. It will beunderstood that the upper and lower forms 282 and 284 are slidable alongthe mandrel 286 but a circular flange 287 at its distal end retains thelower form 284. The upper and lower forms 282 and 284 are substantiallycircular and have a diameter substantially matching the internaldiameter of the well casing 10 and are thereby in substantial contactwith the internal surface 12.

[0061] The sealing system 280 is joined to a workstring 290 having anouter tube 292 and an inner mandrel 293 moveable therein. The outer tube292 extends within aperture 285 and is releasably retained therein by aninterference fit between the exterior of the outer tube 292 and aperture285. The mandrel 286 is preferably formed with the inner mandrel 293 toinclude a shear line 295. As shown in FIG. 6B, in the sealingconfiguration, a sealing material 294 is disposed around the mandrel 286and between the upper and lower forms 282 and 284 to fill cavity 283.

[0062] In operation, the upper and lower forms 282 and 284 areinterconnected with workstring 290 and run into the well casing 10 tothe desired location. The mandrel 286 may then be advanced from theouter tube 292 to establish the required length for the cavity 283. Itwill be understood that the upper and lower forms 282 and 284 may, in anoptional embodiment, act as wipers for mechanically cleaning theinternal surface 12 of the well casing 10 during their relativemovement. Additionally, a chemical wash and activation of the internalsurface 12 surrounding cavity 283 between the lower form 284 and theupper form 282 may be conducted to prepare the internal surface 12 for asealing engagement with a fluidized seal material. After the internalsurface 12 has been prepared, the sealing material 294 may be pumpedthrough passage 296 in outer tube 292 into the cavity 283. The sealingmaterial 294 is then allowed to cure and form a fluid tight, grippingseal with internal surface 12 of well casing 10. The outer tube 292 maythen be withdrawn and mandrel 286 disconnected from inner mandrel 293 atshear line 295 such that the workstring 290 may be removed.

[0063] The upper form 282 is joined to the outer tube 292, such that thelower form 284 and the upper form 282 may be positioned relative to eachother to establish the desired length of the cavity 283 and theresultant length of sealing material 294. In one aspect, the length ofthe sealing material 294 is greater than 12 inches. The length of thecavity 283 may be a function of the properties of the sealing material294 used in consideration of the wellbore temperature and pressuresexpected. The sealing material 294 could be a resin, epoxy, cementresin, liquid glass, or other suitable material known in the art.Further, a setting compound may be mixed with the sealing material 294to actuate curing to a hardened condition.

[0064] It will be appreciated that the mandrel 286 may include a fluidpassageway and valve disposed adjacent to the upper form 282 such thatthe valve may be opened prior to drilling the sealing system 280 toequalize pressure above and below the sealing system 280. It will alsobe understood that the upper and lower forms 282 and 284 may be formedof any desired material including metal, composites, plastics, etc.Furthermore, while two forms members have been shown in the illustrativeembodiment disclosed herein, it will be appreciated that only a singleform would be necessary. Further, while the above described methodcontemplated filling the cavity 283 with a resin or epoxy, it ispossible that the pumping action of the sealing material 294 againstlower form 284 may urge the upper and lower forms 282 and 284 apart fromone another to thereby establish a spaced apart relationship between theupper and lower forms 282 and 284 substantially filled with the sealingmaterial 294.

[0065] Once the sealing system 280 has been set in a sealingconfiguration as described above, it may be left in place to provide aseal between the upper casing passage 32 and the lower casing passage 34while other well operations, known in the art, are performed. Upon thecompletion of the well operations, the sealing member 280 may be removedfrom the wellbore by top drilling the device. During the removalprocedure, a drill member (not shown) may disengage an upper one-wayvalve (not shown), which will, over time, equalize the pressure betweenupper casing passage 32 and the lower casing passage 34.

[0066] The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical application,to thereby enable others skilled in the art to best utilize theinvention and various embodiments with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the invention be defined by the claims appended hereto and theirequivalents.

What is claimed is:
 1. A downhole tool apparatus for insertion into awellbore, the apparatus comprising: a tubular member having an outersurface defining an outer diameter, wherein the tubular member has aninsertion configuration in which the outer diameter defines a firstouter diameter, the tubular member has a set configuration to limitmovement of the tubular member within the wellbore, the outer diameterdefines a second outer diameter in the set configuration, and the seconddiameter is greater than the first diameter; and a gripping memberextending beyond the outer surface of the tubular member, wherein thegripping member is adapted to penetratingly engage a portion of thewellbore when the tubular member is in the set configuration.
 2. Theapparatus of claim 1, further comprising a sealing member extendingbeyond the outer surface of the tubular member, wherein the sealingmember is adapted to seal the wellbore when the tubular member is in theset configuration.
 3. The apparatus of claim 1, wherein the tubularmember has an inner surface defining an internal chamber, and theapparatus further comprises a valve for controlling fluid flow into theinternal chamber.
 4. The apparatus of claim 3, wherein the valve is aone-way valve.
 5. The apparatus of claim 1, wherein the tubular memberis formed of a non-metallic material.
 6. The apparatus of claim 5,wherein the tubular member is formed of plastic.
 7. The apparatus ofclaim 6, wherein the gripping member is embedded in the tubular member.8. The apparatus of claim 1, wherein the tubular member has an open endand a closed end, and the open end is adapted to expand when the tubularmember shifts from the insertion configuration to the set configuration.9. The apparatus of claim 8, further comprising a one-way valve disposedadjacent the closed end for controlling fluid flow between the tubularmember and the wellbore.
 10. The apparatus of claim 8, furthercomprising a second tubular member having an outer surface, an open end,and a closed end, wherein the closed end of the second tubular member iscoupled to the closed end of the tubular member, and the open end of thesecond tubular member is adapted to expand for sealing the wellbore. 11.The apparatus of claim 10, further comprising a second gripping memberextending beyond the outer surface of the second tubular member, whereinthe second gripping member is adapted to penetratingly engage a secondportion of the wellbore.
 12. The apparatus of claim 8, furthercomprising a sealing member extending beyond the outer surface of thetubular member, wherein the sealing member is adapted to seal thewellbore.
 13. The apparatus of claim 1, wherein the tubular member hasan upper end and a lower end, and the apparatus further comprises a plugadapted to be coupled to an internal surface of the tubular member,wherein advancement of the plug from the upper end to the lower endexpands the outer diameter of the tubular member.
 14. The apparatus ofclaim 1, wherein the gripping member further comprises a metal wedgeembedded in the outer surface.
 15. The apparatus of claim 1, wherein thegripping member further comprises a pointed metal member embedded intothe tubular member.
 16. The apparatus of claim 1, further comprising asealing member embedded in the outer surface, wherein the sealing memberis more flexible than the tubular member.
 17. The apparatus of claim 1,further comprising a sealing layer coating a portion of the outersurface, wherein the sealing layer is more flexible than the tubularmember.
 18. The apparatus of claim 1, wherein the tubular member is atleast partially plastically deformable when shifting between theinsertion configuration and the set configuration.
 19. The apparatus ofclaim 1, wherein the tubular member is at least partially elasticallydeformable when shifting between the insertion configuration and the setconfiguration.
 20. The apparatus of claim 1, further comprising asealing member, wherein the tubular member is a non-metallic materialthat expands for gripping and sealing engagement with the wellbore whenthe tubular member shifts from the insertion configuration to thesealing configuration.
 21. The apparatus of claim 20, wherein thegripping member is formed of a material harder than the non-metallicmaterial forming the tubular member.
 22. The apparatus of claim 21,wherein the sealing member is formed of a material softer than thenon-metallic material forming the tubular member.
 23. The apparatus ofclaim 20, wherein the tubular member has a first length in the insertionconfiguration and a second length in the sealing configuration, and thesecond length is shorter than the first length.
 24. A downhole tooldevice for insertion into a wellbore, the device comprising: a tubularmember having an interior surface, wherein the interior surface definesan internal chamber; a ring member coupled to the tubular member,wherein the ring member is in hydraulic communication with the internalchamber, and the ring member is adapted for responding to an increase inpressure in the internal chamber by expanding in a radial direction; agripping member coupled to an exterior surface of the ring member forpenetratingly engaging a portion of the wellbore; and a sealing membercoupled to the exterior surface of the ring member for sealinglyengaging a portion of the wellbore.
 25. The device of claim 24, furthercomprising a valve in fluid communication with the internal chamber. 26.The device of claim 25, wherein the valve is configured to permit fluidflow into the internal chamber and inhibit fluid flow out of theinternal chamber.
 27. A downhole tool device for insertion into awellbore, the device comprising: a tubular member having an outersurface defining an outer diameter and an internal chamber, wherein thetubular member is adapted for responding to an increase in pressure inthe internal chamber by expanding the outer diameter; a gripping membercoupled to the outer surface of the tubular member for penetratinglyengaging a portion of the wellbore; and a sealing member coupled to theouter surface of the tubular member for sealingly engaging a portion ofthe wellbore.
 28. A downhole tool device for insertion into a wellbore,the device comprising: a tubular member having an open end and anopposite closed end, wherein the open end is adapted to expandcircumferentially from a run-in condition to an expanded condition whenexposed to a predetermined amount of pressure; and a gripping membercoupled to an exterior surface of the tubular member, wherein thegripping member engages a portion of the wellbore when the tubularmember is in the expanded condition.
 29. The device of claim 28, furthercomprising a sealing member coupled to the exterior surface of thetubular member, wherein the sealing member is adapted to seal thewellbore when the tubular member is in the expanded condition.
 30. Thedevice of claim 28, further comprising a one-way valve coupled to theclosed end of the tubular member.
 31. The device of claim 28, furthercomprising: a second tubular member having an open end and a closed end,wherein the closed end of the first tubular member is coupled to theclosed end of the second tubular member, and the second tubular memberis adapted to expand circumferentially when exposed to a predeterminedamount of pressure; and a second gripping member coupled to an exteriorsurface of the second tubular member, wherein the second gripping memberengages a second portion of the wellbore when the second tubular memberis expanded circumferentially.
 32. A downhole tool device for insertioninto a wellbore, the device comprising: a tubular body having aninternal surface, an exterior surface, an upper end, a lower end, and alongitudinal axis extending between the upper end and the lower end; aplug adapted to engage the internal surface, wherein advancement of theplug longitudinally from the upper end towards the lower end expands thetubular body circumferentially from an insertion configuration to a setconfiguration; and a gripping member coupled to the exterior surface ofthe tubular body, wherein the gripping member engages a portion of thewellbore when the tubular body is in the set configuration to maintainthe position of the tubular body in the wellbore.
 33. The device ofclaim 32, further comprising a sealing member coupled to the exteriorsurface of the tubular body, wherein the sealing member is adapted toseal the wellbore when the tubular body is in the set configuration. 34.The device of claim 32, wherein the lower end is closed and the upperend is open.
 35. The device of claim 32, further comprising a mandrelcoupled to the tubular body for coupling the device to a tool string,wherein the plug is adapted to longitudinally move along the mandrel.36. A method of sealing a wellbore, comprising the steps of: inserting atubular member having both a gripping element and a sealing element onthe outer surface thereof into the wellbore; and expanding at least aportion of the tubular member to a set configuration, wherein thegripping element engages the wellbore and the sealing element seals thewellbore.
 37. The method of claim 36, wherein the tubular member isnon-metallic.
 38. The method of claim 37, wherein the step of expandingfurther comprises the step of plastically deforming the tubular member.39. The method of claim 37, wherein the step of expanding furthercomprises the step of elastically deforming the tubular member.
 40. Themethod of claim 37, wherein the step of expanding further comprises thestep of urging the gripping element to penetratingly engage thewellbore.
 41. The method of claim 36, further comprising the steps of:coupling the tubular member to a workstring prior to the step ofinserting the tubular member into the wellbore; and disengaging theworkstring from the tubular member after the step of expanding at leasta portion of the tubular member.
 42. The method of claim 36, wherein thetubular member has an internal chamber, and the step of expandingincludes the step of introducing fluid into the internal chamber toexpand the tubular member to the set configuration.
 43. A method ofsealing a wellbore, comprising the steps of: providing a tubular memberwithout an internal mandrel; positioning the tubular member in awellbore; and expanding at least a portion of the tubular member toengage the wellbore.
 44. The method of claim 43, wherein the step ofexpanding is at least in part caused by hydraulic pressure.
 45. Themethod of claim 43, wherein the step of expanding is at least in partcaused by mechanical force.
 46. The method of claim 43, wherein the stepof expanding comprises the step of advancing a plug within the tubularmember to expand the tubular member into engagement with the wellbore.47. The method of claim 43, wherein the tubular member comprises agripping member, and the step of expanding further comprises the step ofengaging the gripping member with the wellbore.
 48. The method of claim43, wherein the tubular member comprises a ring member for engaging thewellbore.
 49. The method of claim 43, further comprising the steps of:coupling the tubular member to a workstring prior to the step ofpositioning the tubular member in the wellbore; and disengaging theworkstring from the tubular member after the step of expanding at leasta portion of the tubular member.